State and explain Gauss's law in magnetism.

Explanation

The net magnetic flux passing normally outward through any closed surface is zero.
i.e , `phi_(B) = oint vecB .dvecs =0`
Consider a smell vector area element d`vecs` of a closed surface. The magnetic flux through d `vecs` is `dphi _(B)= vecB .dvecs `, where , `vecB` is the field at net magnetic flux through the enclosed surface is `phi _(B) = int d phi _(B) = oint vecB.dvecs= 0 `.
This is because the number of magnetic lines of force leaving the surface (` + phi_(B))` will be equal to the number to magnetic lines of force entering the surface `( - phi_(B)). :. "Net" phi = +phi _(B) -phi_(B) = 0`.